1. Field of the Invention
This invention relates generally to the cooling of integrated circuit boards and power electronic components to increase their power density. Most electrically energized equipment is limited in its capacity by thermal constraints. The advent of more electric vehicles such as ships, transportation equipment including cars, trucks, aircraft and trains has pushed the capabilities of many electronic controls to their maximum thermal constraints. These constraints have a direct effect on efficiency, power density, packaging and the architectural configuration for these components in their operating environments.
Each year additional software and hardware is required by electronic systems in order to meet customer expectations, particularly in power electronics. Increasingly there are many applications where significantly higher power is required and space is at a premium. Efficiency and power density may be compromised by the addition of more cumbersome traditional integrated circuit cooling systems utilizing, cold plates and traditional spray cooling methods. There are many applications where this is not a significant issue, however, there are an increasing number of environments, such as with power electronics where power density must be optimized to enable such applications to be commercialized.
One such example is the current interest in the introduction of hybrid/electric propulsion systems in transportation. Power density is a critical factor in determining overall fuel efficiency of the platform. It is critical to reduce an electrical component's size to achieve lightweight, cost-effective components.
The present invention relates to a significantly more effective method and apparatus for the removal of latent heat from integrated circuit boards, integral power busses and their components. It has been found that a significant increase in power density is achieved by utilizing the integrated circuit board and/or their components as the injection source in the spray cooling process. By utilizing the integrated circuit boards and their components two significant factors are accomplished. In the first, the heat is more effectively removed directly from the source of the heat generated. This helps to eliminate any unnecessary high and low pressure regions integral to the environment in which the components are encased. The second factor is the elimination of additional manifolds and injectors to nebulize liquids which add to a system's complexity, requires more space, adds additional cost and increases the relative amount of maintenance.
2. Description of Related Art
U.S. Pat. No. 5,719,444 discloses a packaging and cooling system for one or more semi-conductor devices in which an evaporative type liquid coolant is sprayed from a plurality of spray nozzles onto the semi-conductor devices and the liquid is then condensed, cooled and recirculated by a pump to an input plenum for reuse in a closed circuit.
U.S. Pat. No. 5,880,931 discloses a spray cooled circuit card cage which includes a manifold to provide coolant fluid to a plurality of spray plate assemblies which direct the spray of coolant over the top surface of the electronic cards within the card cage.
U.S. Pat. No. 4,392,153 discloses a semi-conductor electronic device which is attached to fluid cooled heat sinks to provide efficient removal of heat generated by the device,
U.S. Pat. No. 4,573,067 discloses a semi-conductor chip which is provided with fins to provide improved heat dissipation capability.
U.S. Pat. No. 5,239,200 discloses a heat transfer module which is placed into thermal contact with a chip on a circuit board for conducting heat therefrom. The heat transfer module has a channel therein for receiving a coolant.
U.S. Pat. No. 5,345,107 discloses a cooling apparatus for an electronic device in which a cooling body is placed into surface contact with an electronic device.
U.S. Pat. No. 5,049,973 discloses a heat sink for electrical components.
U.S. Pat. No. 5,373,417 discloses a liquid cooled circuit package where the package is filled with a cooling liquid during operation.
U.S. Pat. No. 3,746,947 discloses a semi-conductor device which is positioned with a enclosure which has liquid coolant circulating therein.
None of the foregoing prior art suggested ports, perforations or passageways in either the circuit board, the components themselves, or the conductive leads for the components to promote internal cooling of the components by conduction, and cooling of the surface of the components by evaporative and conductive cooling.